Over the past few years, the physics of low dimensional electronic systems has been revolutionized by the discovery of materials with very unusual electronic structures. Among these, graphene has taken center stage due to its relativistic-like electron dynamics and potential applications in nanotechnology. Moreover, the recent discovery that hexagonal boron nitride (hBN) is a nearly-ideal substrate for high mobility graphene devices has enabled a new generation of quantum transport experiments in graphene. In this talk I will review our recent experiments on few layer graphene devices on hBN. In addition I'll review our optoelectronic experiments on graphene pn junctions, where we observe a hot-carrier mediated photothermoelectric intrinsic graphene optical response.